If it works like most I have run across, yes you do.
At idle there is a vacuum on the regulator, it leans it out and also reduces fuel when in higher vacuum situations such as part throttle cruising.
It will hurt fuel economy, potentially foul plugs, and mess with your AFR.
Jim
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1992 Dark Teal LS-L with 4.44 swap. NC Plate "EVIL I" *Dont Fear the GEAR*
1977 Ford Pinto baby blue with 79,000 miles
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